Increment version to 10.4.0-rc3

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/VERSION b/VERSION
index 583e43a..c00ea05 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-10.4.0-rc2
+10.4.0-rc3